Recently, electrodes for terminals arranged in a test substance such as electronic device substrates for semiconductor integrated circuits and flat panel displays (FPD), or circuit substrates have a tendency to have the pitch thereof becoming minute more and more. Therefore, a probe contact having a minute pitch corresponding to the pitch of these electrodes is required for the side of the energizing test equipment in the energizing test of these electronic devices and circuit substrates.
As a method for manufacturing a probe contact having a minute pitch, the manufacturing method for a probe contact has been disclosed in which leads of an elongated conductive layer are formed on a plane front face of the substrate for contact arranged as far as the end of the substrate by the micro fabrication technology using photolithography, and then a predetermined region of the end of the substrate is cut off in such a manner that the tips of the leads can project from the edge of the substrate (For example, refer to the Patent Literature 1). The cutting method disclosed in the Patent Literature 1 has proposed that a carved groove is formed on the rear face of the edge of the substrate in order that the tips of the leads may come to be resilient armatures projected from the end of the substrate for contact and thereafter the edge of the substrate is fractured along the carved groove. However, this method may give damage such as deformation to the lead when the substrate is fractured.
Consequently, a manufacturing method for a probe contact was proposed to prevent the lead from being damaged when the substrate for contact is fractured (For example, refer to the Patent Literature 2). In this method, the sacrifice layer is formed on a region at the edge of the plain front face of the substrate, and the leads whose tips are positioned on the sacrifice layer are formed by the micro fabrication technology using photolithography, and further a groove passing just under the portion formed on the sacrifice layer of the lead is formed on the rear face of the substrate. Then, the sacrifice layer is removed after the lead is formed, and thereafter the substrate is to be fractured along the groove.
However, the method of fracturing the substrate for contact is prone to generate dispersion with respect to the fracturing position of the front face side at the end of the substrate after it is fractured. The reason is that though it is indispensable to align the groove in compliance with the position of the lead on the front face of the substrate or the position of the sacrifice layer at the process of forming the groove on the rear face of the substrate, dispersion inevitably occurs at this alignment. Furthermore, dispersion of the fracturing position on the substrate is affected by the practice of compressing when it is fractured. In some cases, the fracturing position does not go along the direction of the groove formed in a predetermined region of the rear face of the substrate elongated linearly, but may meander.
Dispersion of the fracturing position is directly connected to dispersion of the length of the resilient armature, and is greatly affected to the quantity of resilient bending and rubber elasticity. As a result, it varies the contact pressure to the electrode for the terminal of the test substance. Additionally, meandering of the fracturing position causes unevenness of the contact pressure over a plurality of leads. If the fracturing position is out of the proper region and does not clear the product specification in manufacturing of the probe contact, the probe contact comes to be defective and production yield thereof is decreased. Such dispersion of the fracturing position including meandering is a problem that comes to be obvious as the above-mentioned electrodes are developing into those with a minute pitch and thereby the lead thereof comes to be fine.
Though it is conceivable that the thickness of the substrate is reduced as a measure to solve the problems mentioned above, unevenness of the contact pressure over a plurality of leads due to undulation or warp of the substrate is on the contrary actualized in this case.
Patent Literature 1: Laid-Open Patent No. H08-15318
Patent Literature 2: Laid-Open Patent No. 2007-3263